A method of sealing an aircraft wing vent stringer may include placing a movable sealant sled in a vent stringer cavity of an aircraft wing. The sealant sled may include a sealant source configured to apply sealant to a wing portion within the vent stringer. The sealant sled may be transported through the cavity in a longitudinal direction defined by the wing, thereby applying a layer of sealant to the wing. In some cases, vent stringer may be abraded and/or washed before sealing. In some cases, two or more layers of sealant may be applied, one of which may be a secondary fuel barrier.